1. Field of the Invention
The present invention relates to a signal line connector and, more specifically, to an improved structure of signal line connector, which has the locating barrel so made to fit different signal lines of different sizes and to maintain the sense of beauty of the outer appearance of the signal line connector intact after installation.
2. Description of the Related Art
A conventional signal line connector is known comprising a connector body affixed to a thin tube for accommodating a signal line. After insertion of a signal line into the connector body and the thin tube, a crimping device is used to crimp and distort the thin tube, causing the thin tube to be fixedly secured to the signal line. When crimping the thin tube, the thin tube may break along its seam line. Therefore, a contact error may occur, or the signal line may be separated from the signal line connector when the signal line stretched. There is also known a coaxial cable connector in which a socket is rotatably coupled to a hollow cylindrical casing and defines with the casing an annular space, and a locating member having an axially extended tapered hole is sleeved onto the rear extension of the barrel for squeezing the socket to hold down a coaxial cable. The installation procedure of this design is complicated. If the coaxial cable is curved or stretched during installation, the locating member tends to be vibrated and loosened, resulting in a contact error or disconnection of the coaxial cable.
FIGS. 7 and 8 show a signal line connector A according to the prior art, which is comprised of a locknut B, a center holding down tube C, a hollow cylindrical casing D, and a locating barrel E. The locknut B has an inner thread B1 in the rear end, and a coupling portion B2 in the front end. The center holding down tube C is coupled to the coupling portion B2 of the locknut B, having a tube body C3, a barbed portion C31 at the front end of the tube body C3, a receiving portion C2 at the rear end of the tube body C3, and a passage hole C1 axially extended through the receiving portion C2, the tube body C3 and the barbed portion C31. The hollow cylindrical casing D is mounted on the center holding down tube C, having a coupling neck D1 axially extended from the rear end, a rear coupling hole D2 and a front coupling hole D3 axially aligned in a line and respectively extended through the rear and front ends, and an inside annular groove D31 extended around the inside wall in the front coupling hole D3. The locating barrel E is plugged into the front coupling hole D3 of the hollow cylindrical casing D, having a receiving hole E1 axially extended through the front and rear ends, an inside annular flange E11 extended around the inside wall in the receiving hole E1, a first outside annular flange E21 around the rear end of a periphery E2, and a second outside annular flange E22 around a middle part of the periphery E2. During the assembly process, a gasket ring D4 is mounted on the coupling neck D1 of the hollow cylindrical casing D, and then the center holding down tube C is plugged into the rear end of the hollow cylindrical casing D to engage the receiving portion C2 in the rear coupling hole D2 of the coupling neck D1, and then the center holding down tube C is fastened with the coupling neck D1 of the hollow cylindrical casing D to the coupling portion B2 of the locknut B, and then the locating barrel E is plugged into the front coupling hole D3 of the hollow cylindrical casing D to engage the first outside annular flange E21 of the locating barrel E into the inside annular groove D31 of the hollow cylindrical casing D.
After installation of a signal line F in the locating barrel E and connection of the locating barrel E with the signal line F to the hollow cylindrical casing D (see also FIG. 9), this design of signal line connector shows drawbacks as follows:                The periphery E2 of the locating barrel E is not greatly deformable to fit different signal lines F of different diameters, therefore a different size of locating barrel E shall be used to fit a different size of signal line F.        When plugging the locating barrel E with the signal line F into the front coupling hole D3 of the hollow cylindrical casing D after installation of the signal line F in the locating barrel E, the periphery E2 of the locating barrel E is squeezed to deform (see FIG. 9), thereby causing the part of locating barrel E that extends out of the front coupling hole D3 of the hollow cylindrical casing D to curve. Curving of the protruded part of the locating barrel E destructs the sense of beauty of the signal line connector, and results in a gap between the inside wall of the hollow cylindrical casing D and the outside wall of the locating barrel E.        